Posted: 12/05/2013 at 20:59
The yellowing leaves sound like it's suffering from lime chlorosis. Even if it's planted in acid soil/compost it will still need an ericaceous feed, especially if it's in a pot.
Lack of flowers, can be due to lack of water (again especially if it's in a pot), overfeeding - too comfortable, or underfeeding. I always give mine a feed in Spring and again in Autumn. Wherever possible the ones in pots I water with rain water